1. Field of the Invention
This invention relates to a method for providing an easy opening device for envelopes, and in one aspect, to an opening device for use with bags formed of nonwoven tough thermoplastic fibers.
2. Description of the Prior Art
Mailing envelopes or shipping bags formed of a tough sheet material incorporating nonwoven thermoplastic fibers are commonly used by parcel carrier services. These envelopes are formed with a flap having a very aggressive pressure-sensitive adhesive disposed under a removable liner. After the bag is filled, the liner is removed from the pressure-sensitive adhesive (psa) and the flap is closed over the back panel of the envelope and seals the envelope flap securely. To remove the contents from the envelope it is often necessary to obtain a scissors to cut the bag along one edge.
Tear strips are placed on paper envelopes which permit one to grasp the end of the tear strip or tear tape and by pulling on the tear tape and holding the envelope a tear is placed in the area of the tear tape across the envelope. Because of the toughness of the fibers forming the envelopes used in the present invention, the application of a tear tape to the inner face of the envelope and pulling the same will not produce a tear in the web material forming the envelope.
It is therefore an object of the present invention to provide a method and apparatus for forming a tear opening structure on a bag or envelope formed of nonwoven thermoplastic fiber material such as polyolefin.
It is a further object of the present invention to provide a method of forming an easy open system on a nonwoven thermoplastic fiber formed envelope which will make the envelope as secure as the same is without the easy opening system but yet allow easy access to the envelope when desired.
It is a further object of the present invention to provide a process for making an easy open score line in a tough nonwoven polymeric fiber web.
It is a further object of the present invention to provide a novel envelope formed by the method of the present invention.